The present invention relates to a finishing agent of fibers or, more particularly, to a silicone-based softening agent of waddings of synthetic fibers capable of giving excellent softness to the treated wadding without the disadvantage of yellowing of the wadding caused by heat or in the lapse of time.
Waddings of synthetic fibers such as polyester fibers and acrylic fibers are required to give a pleasant touch of smoothness and softness which can be imparted thereto by a treatment with a softening agent. Various kinds of softening agents have been developed and used in the prior art.
Known softening agents suitable for the purpose include, for example, a combination of an epoxy-modified organopolysiloxane and an amino-substituted organopolysiloxane, a combination of an epoxy-modified organopolysiloxane and an organic amino compound and a combination of an aminosubstituted organopolysiloxane and an organic epoxy compound disclosed in Japanese Patent Publication No. 48-17514, a combination of a high-polymeric dimethylpolysiloxane and an aminoalkoxy silane disclosed in Japanese Patent Publication No. 51-37996, a combination of an epoxy-modified organopolysiloxane and an aminoalkoxy silane disclosed in Japanese Patent Publications Nos. 53-19715 and 53-19716, and so on. These softening agents of prior art are each effective to impart waddings of synthetic fibers with smoothness and softness to exhibit a pleasant feeling of touch something like light feathers.
These silicone-based softening agents of prior art, however, have a very serious problem that the wadding of synthetic fibers treated with the softening agent are subject to yellowing already in the course of the treatment involving a step of heating or in the lapse of time during storage or use so that the commercial value of the wadding is greatly decreased. Therefore, it is eagerly desired in the fabric industry to develop a softenig agent for synthetic fiber-made waddings improved in this regard.